Known in the art is a method for upward development of thick beds of horizontal layers with filling of developed space (V. R. Imenitov, Processes of Underground Mining in Development of Ore Deposits, Nedra Publishers, 1984, Moscow, pp. 434-439). Accomplishment of the known method calls for using a hardening filling because a successive layer is extracted from a previously laid layer along which self-propelled face equipment moves. In order to maintain using self-propelled equipment, inclines extend between transport and fan drifts in the inter-room pillars giving access to haul cycles in each layer. Free space 3.5 m high is left between ore mass and the laid layer. Individual layers of the same thickness of a bed are processed by way of explosive drilling.
The known method fails to provide intensive treatment for the individual extraction of a mineral, because the process cycle provides for alternating processes of extraction and laying which are incompatible in time and space. In addition, the known method calls for driving from the transport inclines of the drives to each layer, thus appreciably increasing the volume of preparatory work.
Known in the art is a method of developing thick beds (SU,A,1011861) comprising the preparation of the room for winning and the winning proper. Preparation of the room for winning consists of conveyer working and the installation of a conveyer therein, cropping of the room neck, and driving of the transport and fans drifts.
Winning is effected in layers from top to bottom. The room is developed in two layers. First, the layers are developed from top to bottom, i.e., in a descending order, in one part of the room with the formation of a temporary inclined descent along the entire width of the room and its entire height. Thereupon, using this inclined descent in layers from top to bottom, the second part of the room is developed. The inclined descent is formed due to the fact that each layer underneath is developed shorter than the preceding one to a length that ensures the formation of a safe angle of descent for self-propelled vehicles.
Development of the first layer comprises consecutive extraction of a number of stopes as to the width of the room with the application of the cutting machine runnings. The development of the second and subsequent layers also resides in consecutive extraction of stopes relative to the room width, but with the application of the machine runnings not only relative to the room width, but also the room height.
Development of each layer begins with extracting the first stope adjacent to the room edge with the formation of blind drive-ins, opening the raises and permitting switching and unloading of the means of haulage.
At the end of the first stope the cutter-loader is turned through 180.degree. and using a reverse motion the second adjacent stope is extracted. Once the second stope is extracted, the machine is again turned through 180.degree. to start extracting the third stope adjacent to the second and so on and so forth. Following the development of one layer, the cutter-loader, moving along the slope downwards, gets deeper into the second layer, thereupon, the first stope of the second layer is extracted. Then, the rest of the stopes of this layer are developed, whereupon, using the formed part of the temporary inclined descent, the machine is deepened to a third layer and so work goes on until the soil of the room is removed.
The remaining part of the room reserves is developed at the second stage in an analogous manner to be used for cutting the temporary descent layer.
The known method is characterized by a low efficiency in the use of machine complexes and fails to provide a high level of operation safety at the second stage for the following reasons:
1. Development of room reserves in two stages with the formation of a temporary inclined descent across the entire width of the room and final development of the remaining part of the room reserves from this inclined descent makes it necessary for the machine to operate in each layer and each stope (in the zone of inclined descent) by incomplete section of the actuator (the machine technical possibilities are not efficiently used). This method also requires the running of machine complexes with stopes of variable length. In so doing, for each type of equipment, an optimal length of delivery is predetermined (length of the room of stope), whereby the cutter-loader does not stay idle awaiting the arrival of transporting means.
Meanwhile, as the inclined descent is formed at the first stage and in the beginning of each layer at the second stage, the machine in each stope operates with an incomplete usage of the actuator section to section to cause a decline in the machine output and additional dynamic loads on the machine impairing its reliability and service life.
2. Extraction of the first stope in each layer near the room edge involves the formation of blind drive-ins to the raises along the entire length of the room requires additional driving and operation of blind curvalinear drive-ins in each layer.
The operation of cutter-loaders in curvalinear sections reduces their output and takes more time for survey control over the direction when driving these drive-ins. In so doing, the formation of blind drive-ins characteristics of the known method appreciably complicates self-propelled vehicles' maneuvers, calls for additional time for their U-turns in drive-ins, which doubtless affects the output of complexes and call for using a large number of machines and service personnel. Also, the presence of these drive-ins rules out the possibility of using a continuous means of delivery.
3. Conveyer working along the soil of the lower layer while preparing the room for winning creates additional complexities for full development of the two lower layers of the room by complexes of machines. This is so because it is not ruled out that a machine can fall through to this heading on a delivery conveyor.
4. Preparation of the room neck, as it gets ready for winning operations, presupposes using different types of equipment and the technique of explosive-drilling extraction during the neck preparation and the extraction by machine--during winning operations.
5. Suppression, which is characteristic of the known method in the inclined descent formed along the entire width and height of the room at the first stage of winning, deprives the room of communication with a fan drift and simple and reliable safety escapes, because consecutive downward suppression by layers of the inclined descent at the second stages will remove the layer being worked from the fan drift, and communication with it will be fairly difficult or impossible in general.